The present invention relates to a horizontal type compressor which comprises a driving element in a horizontal type airtight container, and a compression mechanism section driven by the driving element, and compresses a refrigerant at the compression mechanism section to discharge the refrigerant.
A conventional rotary compressor of such a kind, especially a rotary compressor of a multistage compression system which comprises a compression mechanism section constituted of first and second rotary compression elements, is constituted by arranging a driving element in an upper part in a normal vertical type airtight container, and the compression mechanism section driven by a rotary shaft of the driving element in a lower part. A refrigerant gas is sucked through a suction port of the first rotary compression element into a low-pressure chamber side of a cylinder, compressed by operating a roller and a vane, and discharged from a high-pressure chamber side of the cylinder through a discharge port and a discharge muffling chamber into the airtight container. At this time, intermediate pressure is set in the airtight container (e.g., see Japanese Patent Application Laid-Open No. 2-294587).
The refrigerant gas of the intermediate pressure in the airtight container is sucked through a suction port of the second rotary compression element into the low-pressure chamber side of the cylinder, and subjected to compression of a second stage by operating the roller and the vane to become a high-temperature and high-pressure refrigerant gas. The refrigerant gas is then passed from the high-pressure chamber side through the discharge port and the discharge muffling chamber to flow into a radiator outside the compressor.
In the vertical type rotary compressor, a bottom part positioned below the compression mechanisms section in the airtight container is used as an oil reservoir. Oil is sucked from the oil reservoir by an oil pump disposed in a lower end of the rotary shaft, and supplied to the compression mechanism section, whereby abrasion of the compression mechanism section and a sliding part of the rotary shaft is prevented, and sealing is secured.
Among such rotary compressors, there is a type in which an airtight container is horizontally installed to reduce a height. In this case, a rotary shaft is extended in a horizontal direction, and first and second rotary compression elements are arranged side by side left and right.
In the cylinder which constitutes the second rotary compression element of the rotary compressor of the multistage compression system, pressure becomes higher than the intermediate pressure in the airtight container. The oil dissolved in the refrigerant sucked into the second rotary compression element is separated therefrom at a stage in which the refrigerant is discharged into the airtight container. Accordingly, oil supplying into the cylinder of the second rotary compression element becomes difficult, causing a problem of oil running-out.
If such a rotary compressor is used as a horizontal type, the oil supplied to the first rotary compression element is dissolved in the refrigerant gas compressed by the same, and the oil stays not only in the oil pump side but also in the bottom part of the airtight container of the driving element side. Consequently, there is a fear that oil suction by the oil pump constituted in the end of the compression mechanism section side of the rotary shaft may not be smooth.
Additionally, the oil mixed in the refrigerant gas compressed by the first rotary compression element is discharged into the airtight container, and separated from the refrigerant gas to a certain extent in a process of movement in a space of the airtight container. However, the oil mixed in the refrigerant gas compressed by the second rotary compression element is directly discharged with the refrigerant gas to the outside of the compressor.
Consequently, oil becomes short in the oil reservoir, and oil suction by the oil pump is not smoothly executed, causing a problem of reductions in sliding performance and sealing performance. Moreover, there is a fear that a refrigerant circuit may be adversely affected, e.g., interference with refrigerant circulation in the refrigerant circuit by the oil discharged to the outside of the compressor.
Furthermore, in order to prevent the oil discharging to the outside of the compressor, an oil separator is connected to a refrigerant discharge tube to separate oil from a discharged refrigerant gas, and to return it to the compressor. However, there is a problem of an expanded installation space, or the like.